In order to make aircraft passengers comfortable, and in order to transport them between an airport terminal building and an aircraft in such a way that they are protected from the weather and from other environmental influences, passenger loading bridges are used which can be telescopically extended and the height of which is adjustable. For instance, an apron drive bridge in present day use has a plurality of adjustable modules, including: a rotunda, a telescopic tunnel, a bubble section, a cab, and elevating columns with wheel carriage. Of course, other types of bridges are known in the art, such as for example radial drive bridges and pedestal bridges.
Unfortunately, there are a number of disadvantages associated with the use of passenger loading bridges at an airport. For instance, the process of aligning the passenger loading bridge with the aircraft is time consuming, which increases aircraft turn-around time and causes inconvenience to passengers aboard the aircraft. First, the pilot taxis the aircraft along a lead-in line to a final parking position within a gate area adjacent to the passenger loading bridge. Typically, the lead-in line is a physical marker that is painted onto the tarmac and which is used for guiding the aircraft along a predetermined path to a final and predetermined parking position. Additional markings in the form of stop lines are provided at predetermined positions along the lead-in line. Thus, when the nose gear of a particular type of aircraft stops precisely at the stop line for that type of aircraft, then the aircraft is known to be at its final parking position. Of course, the pilot's view of the tarmac surface from the cockpit of an aircraft is limited. This is particularly true for larger aircraft, such as for instance a Boeing 747. Typically, therefore, the pilot relies upon instructions that are provided by one of a human ground marshal and up to two “wing walkers” and an automated docking guidance system for guiding the aircraft along the lead-in line. Alternatively, a tractor or tug is used to tow the aircraft along the lead-in line to its final parking position.
After the aircraft has stopped at its final parking position, the passenger loading bridge is aligned with a doorway of the aircraft, which in the case of an apron drive bridge may involve extending the bridge by 15 to 20 meters or more. Driving the bridge over a long distance is very time consuming because often the rate at which the bridge is moved is limited in order to reduce the risk of colliding with ground service vehicles or personnel, and to avoid causing serious damage to the aircraft in the event of a collision therewith. Manual, semi-automated and fully-automated bridge alignment systems are known for adjusting the position of the passenger loading bridge relative to the parked aircraft.
As mentioned above, the lead-in lines are permanent markings painted onto the tarmac surface for guiding aircraft of different types to predetermined parking positions. The predetermined parking positions are determined during an airport planning stage. For instance, the airport planning stage includes a step of anticipating future usage for a period of approximately twenty years. Thereafter, a plan is drawn up showing an optimized distribution of the passenger loading bridges at the airport, based upon the anticipated future usage. Once the optimized distribution of the passenger loading bridges is known, the parking positions for different types of known aircraft are determined. For instance, different lead-in lines and stop lines are determined for large aircraft and for small aircraft at each passenger loading bridge. Optionally, same lead-in lines are used both for large aircraft and for small aircraft at some of the airport gates. Accordingly, aircraft of a same type always stop at approximately a same parking position at a same airport gate. Furthermore, the aircraft when stopped are spaced apart sufficiently to provide an adequate clearance between adjacent aircraft.
Of course, unexpected events or changing travel patterns may result in actual usage that is very different from the anticipated future usage. For instance, many airports currently are servicing a larger than anticipated number of commuter jet aircraft on a daily basis. Due to imperfect foresight on the part of the airport planners, commuter jet aircraft often are parked according to the lead-in lines that were originally designed for substantially larger aircraft, which translates into a less than optimal utilization of the airport apron space. Another problem that is often encountered at existing airports occurs when an unusually large number of large aircraft are being loaded or unloaded during a same overlapping period of time. For instance, some passenger loading bridges are taken out of service temporarily in order to free up additional apron space and to accommodate the large aircraft. Unfortunately, other aircraft may be required to stand-by until the large aircraft moves away from the terminal building, despite the fact that one or more passenger loading bridges remain unassigned. Under operating conditions such as these, a less than optimal use is being made of the available passenger loading bridge resources at the airport terminal.
Another limitation of the prior art is that a substantial amount of planning and analysis is required whenever additional passenger loading bridges are to be added at an existing terminal building. As during the initial airport planning stage, future usage must be anticipated and new aircraft stopping positions determined. It may be determined that, due to apron space considerations, some of the new passenger loading bridges must be restricted to servicing only certain types of aircraft, which could adversely affect the airport's ability to assign gates. Often, an additional terminal building is simply constructed when the current design of an airport approaches full capacity. This is undesirable, as the cost of an additional terminal building is very high relative to the cost of adding additional passenger loading bridges at an existing terminal building.
Similar problems to those mentioned above are also expected when a stretch version of an existing type of aircraft comes into service. The stretch version of an aircraft is longer and may additionally have a wider wingspan than its predecessor. For example, a 737-900 is ten feet eight inches longer than a 737-800 and has a wingspan that is four feet ten inches greater than that of a 737-800. Furthermore, many modern aircraft have an approximately vertically extending winglet mounted at each wingtip. Such winglets are standard equipment on certain models of aircraft, and are available as a retrofit item on certain other models of aircraft. However, the winglets do not extend absolutely vertically above the wing, and as such the winglets when present may increase the effective wingspan of a particular model of aircraft. Accordingly, it is necessary that an airport is able to adapt not only to different combinations of aircraft models, but also to combinations of aircraft including different sizes of a same model of aircraft and aircraft having winglets extending beyond the wingtip of the actual wing.
It would be advantageous to provide a method and a system for parking aircraft at a terminal of an airport that overcomes the above-mentioned limitations of the prior art.